Biology - Chapter 3 Section 2
What does a consumer in a food chain depend on for energy?
> Consumers make up the second, third, or higher trophic levels. > Each consumer depends on the trophic level below it for energy.
What are autotrophs?
> Only plants, some algae, and certain bacteria can capture energy from sunlight or chemicals and use that energy to produce food. > These organisms are called autotrophs. > Because they make their own food, autotrophs are called producers.
What does a PYRAMID OF NUMBERS show?
> Pyramid of Number shows the relative number of individual organisms at each trophic level. (page 73 - see diagram)
Describe ENERGY PYRAMID.
> Shows the relative amount of energy available at each trophic level. > Only part of the energy that is stored in one trophic level is passed on to the next level. (page 72 - see diagram)
What is chemosynthesis?
> Some autotrophs can produce food in the absence of light. > When organisms use chemical energy to produce carbohydrates, the process is called chemosynthesis.
Where do bacteria that carry out chemosynthesis live?
> Some chemosynthetic bacteria live in very remote places on Earth, such as volcanic vents on the deep-ocean floor and hot springs in Yellowstone Park. > Others live in more common places, such as tidal marshes along the coast.
What do autotrophs do during photosynthesis?
> The best-known autotrophs harness solar energy through a process known as photosynthesis. > During photosynthesis, these autotrophs use light energy to convert carbon dioxide and water into oxygen and energy-rich carbohydrates.
Why is it that only part of the energy stored in one tropic level is passed on to the next level?
Organisms use about 10 percent of the energy for life processes. The rest is lost as heat. (page 72)
Name the types of Heterotrophs
1. Herbivore 2. Carnivores 3. Omnivore 4. Detritivore 5. Decomposer
For each of the following, write which kind of autotroph is the main producer ... a. Land b. Upper layers of ocean c. Tidal flats and salt marshes
a. Land --> Plants b. Upper layers of ocean --> Algae c. Tidal flats and salt marshes --> Photosynthetic bacteria
What is BIOMASS?
> Biomass represents the total amount of living organic matter at each trophic level. > Typically, the greatest biomass is at the base of the pyramid. > Biomass is usually expressed in terms of grams of organic matter per unit area. (page 72 - see diagram)
Why are autotrophs also called producers?
They make their own food
Define Carnivores and give examples.
Carnivores eat animals. Examples: Snakes, Dogs, and Owls.
Define Decomposer and give examples.
Decomposers break down organic matter. Examples: Bacteria and Fungi.
Plant and animal remains and other dead matter are collectively called _____.
Detris
Define Detritivore and give examples.
Detritivores feed on plant and animal remains and other dead matter. Examples: Mites, Earthworms, Snails, and Crabs.
What is a tropic level?
Each step in a food chain or food web is called a trophic level.
Why can each trophic level support only about one tenth the amount of living tissue as the level below it?
Each trophic level harvests only about one tenth of the energy from the level below it.
Heterotrophs are also called _______.
Heterotrophs are also called consumers. Notes: > Many organisms cannot harness energy directly from the physical environment. > Organisms that rely on other organisms for their energy and food supply are called heterotrophs.
Define Omnivore and give examples.
Omnivores eat both plants and animals. Examples: Humans, Bears, and Crows.
What is at the core of every organism's interaction with the environment?
At the core of every organism's interaction with the environment is its need for energy to power life's processes.
What source of energy do organism use that don't use the sun's energy?
In a few ecosystems, some organisms obtain energy from a source other than sunlight. Some types of organisms rely on the energy stored in inorganic chemical compounds.
Feeding Relationships ... Give a description of a FOOD WEB.
> Ecologists describe a feeding relationship in an ecosystem that forms a network of complex interactions as a food web. > A food web links all the food chains in an ecosystem together.
What is an ecological pyramid?
> The amount of energy or matter in an ecosystem can be represented by an ecological pyramid. > An ecological pyramid is a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web.
Name the three ecological pyramids that Ecologists recognize.
> energy pyramids > biomass pyramids > pyramids of numbers
What does a Biomass Pyramid represent?
A biomass pyramid represents the amount of potential food available for each trophic level in an ecosystem.
Feeding Relationships ... Give a description of a FOOD CHAIN.
A food chain is a series of steps in which organisms transfer energy by eating and being eaten.
What does a food web link together?
A food web links all the food chains in an ecosystem together.
How does energy flow through an ecosystem?
Energy flows through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers).
Define Herbivore and give examples.
Herbivores obtain energy by eating only plants. Examples: Cows, Caterpillars, and Deer.
In a food web, what organisms make-up the first trophic level?
Producers make up the first trophic level.